Don't bet on a mighty El Ni?o: It likely wouldn't help North Coast anyway, officials say

A powerful El Ni?o that had been emerging in the Pacific Ocean is fizzling out, evaporating hopes it will deliver a knockout punch to California's three-year drought.

A new report from scientists at the National Oceanic and Atmospheric Administration decreases the probability of an El Ni?o — the condition that occurs when warm Pacific Ocean water at the equator affects the jet stream — to 65 percent starting in October, down from 82 percent in June.

More significantly, researchers said, the ocean water that had been warming steadily through the spring has cooled off in recent months.

On the North Coast, National Weather Service hydrologist Reginald Kennedy said the events don't usually bring any significant changes to the area's rainfall — unlike regions farther south. In fact, the weather phenomenon tends to delay the rainy season by a month.

"Typically, it doesn't have any significant impact," Kennedy said. "This year, it would just prolong the dry conditions until November."

What to expect

Most of the world's leading meteorological organizations now say that if an El Ni?o arrives this winter, it is likely to be a weak or moderate one — not the kind historically linked with wetter-than-normal winters in California.

"It's fair to say that it's plateaued," said Michelle L'Heureux, a meteorologist with the NOAA Climate Prediction Center in College Park, Maryland.

Other researchers are more blunt.

"We're back to square one. It's finished. I don't think we even have an El Ni?o any more," said Bill Patzert, a research scientist and oceanographer at NASA's Jet Propulsion Laboratory in Pasadena.

"If I were a betting man, I'd say it's 75 percent that we'll have another dry winter," he said. "The unfortunate fact is that it looks like the last three years all over again."

To be sure, California could still have a wet winter to help fill depleted reservoirs, replenish streams and raise over-pumped water tables.

If a steady series of low-pressure systems develops off the Pacific Coast later in the year, that could bring tropical storms dumping rain in large amounts. The trend, known as an "atmospheric river" or "Pineapple Express," has soaked the state in the past. But it has been all but shut down over the past three years as unusually persistent ridges of high pressure off the coast pushed winter storms north to Canada instead.

But the possibility that a strong El Ni?o won't be there to help is "not good news, especially if we are using El Ni?o as an optimism index. It's not what we want to see," said meteorologist Jan Null, with Golden Gate Weather Services in Saratoga.

"It's like in poker," he added. "If you have one fewer spade out there, the odds of getting that flush are less."

The breakdown

Generally speaking, the warmer the ocean water during El Ni?o years, the greater the likelihood of heavy winter rainfall. During mild El Ni?o years, when the ocean water is only slightly warmer than historic averages, there are just as many drier-than-average winters in California as soaking ones.

Since 1951, there have been six winters with strong El Ni?o conditions. But in the 16 winters since 1951 when there was a weak or moderate El Ni?o, California experienced below-normal rainfall in six of them. There was average rainfall in five and above-normal precipitation in the other five.

Of the five significant events, Kennedy said only three produced significant rainfall on the North Coast, and of the seven weaker El Ni?o years, only two produced above average rainfall.

"The biggest thing to take away is if people are hoping a weak El Ni?o would increase our chances for normal precipitation, you just can't count on that," Kennedy said. "What we need is a kind of normal winter pattern to set up to bring the winter storms and the rain."

Thursday's NOAA report was based on ocean temperature readings from dozens of buoys, wind measurements, satellite images and more than a dozen computer models from scientific agencies around the world.

In April, the report noted, Pacific Ocean waters were nearly 4 degrees Fahrenheit warmer than normal along the equator from the surface down to about 1,000 feet deep. But by last month, they had cooled, and are now half a degree cooler than normal. Wind bursts from Indonesia that had pushed warm water toward South America and the United States diminished. And huge amounts of heat dissipated and failed to trigger weather changes in the atmosphere.

"We've seen very lackluster atmospheric response," said NOAA's L'Heureux. "What typically happens with warm water in the eastern Pacific is that you see rainfall and winds shifting around. But it didn't happen. It didn't coalesce."

As a result, none of the world's major meteorological agencies forecast strong El Ni?o conditions this year. Most expect that Pacific waters will range from 1 to 2 degrees Fahrenheit warmer than the historic average this fall, which would signal a weak El Ni?o.

The last strong El Ni?o event, in the winter of 1997-98, saw Pacific surface temperatures 5 degrees warmer than normal at some times. That led to drenching rainfall across California, landslides that closed Highway 1 in Big Sur and 35 counties being declared disaster areas.

Drought conditions

After three drier-than-normal years, major California reservoirs — from Trinity to Oroville to San Luis — are only 20 to 35 percent full. Farmers in the Central Valley are furiously pumping groundwater wells to keep crops alive. The danger of fire is extreme. And last month, the State Water Resources Control Board passed mandatory rules that prohibit all Californians from washing down pavement, irrigating lawns so much that water runs into the street and other excessive practices. Violators face fines of up to $500.

A major concern on the North Coast is the potential for fish kills in the Klamath River and its tributaries due to low water flows and high temperatures. After a recent population survey on the Salmon River found 54 dead adult steelhead trout and spring-run chinook salmon along with hundreds of dead juveniles.

To further protect the fish populations in the unregulated tributary, six state, tribal and environmental agencies and groups created a poster asking North Coast residents and visitors not to disturb the cold water areas these fish are swimming in.

National Marine Fisheries Agency Klamath Branch Program Chief Jim Simondet said the main species of concern is the spring-run chinook salmon.

"There is not a lot left, there is not a lot," he said. "Those adults are precious. They are coming into a system that's really stressed this year."

As water temperatures increase and stress levels rise, Simondet said the fish are more likely to become sick and contract parasites that cause gill rot disease.

"If people see schools of fish in pools they like to swim in, they should avoid those areas," he said. "If you're swimming amongst a large group of fish that are pretty much stranded to deep cool locations of the Salmon River, those fish are gonna stress out."

Future options

If the drought drags into a fourth year, dozens of cities across California will see strict water cutbacks, including rationing, said Jay Lund, a professor of civil and environmental engineering at UC Davis. The state, he said, also is more likely to put in place rules regulating groundwater pumping and other long-delayed water efficiency reforms.

"It takes big droughts to make big changes in water policy in California," Lund said. "It would cinch the deal if we have another dry year."